The present invention relates to rodent traps in general, and more particularly to traps employing a base, a jaw, a trigger, and a spring between the base and the jaw.
Bait containing rodenticide is widely used to control or eliminate rodent populations, however, there are circumstances where mechanical traps are desirable. Traps are useful within large structures or where water is available within a structure such that rodents which consume rodenticide are likely to die within the confines of a structure. Typically, rodenticide causes rodents to become thirsty before death, causing them to leave the typical home or building in search of water. If the rodents do not leave the structure before dying they often die in inaccessible locations. The decay of dead rodents will produce an undesirable stench within a building.
Mechanical traps also allow visual assessment of rodent population. Even where bait containing rodenticide is used, traps may be employed to monitor rodent population. Mechanical traps are also used where foodstuffs could be contaminated by rodenticide.
In homes where small children or pets are present, mechanical traps do not expose non-targeted animals and children to poison.
Mechanical traps, however, have liabilities. They may be constructed of sheet metal which tends to corrode. Corrosion may affect the reliable operation of a trap and will certainly limit its operating life, particularly in damp environments. Mechanical traps also can cut a rodent caught within the trap, causing bleeding which soils the trap and the structure surrounding the trap. Mechanical traps can also be difficult to set. A rodent trap requires a sensitive trigger which often means they are very sensitive to slight movements when being set, and sometimes will be accidently triggered when being positioned. Many mechanical traps also can become enmeshed with the trapped rodent, making discharge of the dead rodent from the trap difficult, thus complicating trap reuse. Where children or pets are present, any trap which will produce an open wound which may become infected is undesirable.
One class of traps typically made of sheet metal, but in some cases constructed of plastic, has four pieces: a base, a jaw pivotally mounted on the base, a trigger mounted on the base, and a coil spring extending between the base and the jaw. This type of trap may be arranged so that the trigger which moves the jaw a small amount and which brings the line of effort produced by the spring through the pivot center, causing the trap to close. Traps based on this basic form have been known since at least the patent to Evans, U.S. Pat. No. 2,138,092, issued in 1938. Traps of the Evans type combined simplicity with the absence of a trigger catchment or sere. This type of trap can often be manipulated externally by pivoting the jaw with respect to the base to release a dead rodent or to set the trap.
Although such traps are known, improvements in manufacturing simplicity, use of plastic materials, ease of operation, and reduction in too sharp edges remain desirable goals.
The rodent trap of this invention has three molded plastic parts: a base, a jaw pivotally mounted on the base, and a trigger mounted on the base. A coil spring extends between the base and the jaw. The base is substantially rectangular; however, the front portion has somewhat greater width than rear portion, and has rounded teeth which extend around three sides. Rearward of the teeth, the sides extend upwardly forming flanges which support small stub shafts which define a pivot axis. The upper jaw mounts to the stub shafts for pivotal movement about the pivot axis. The upper jaw has a forward portion having teeth that are opposed to and which interdigitate with the lower teeth. The jaw rocks on the pivot axis from a position where the jaw teeth engage the base teeth, to a position where a rearmost portion of the jaw engages a rearward portion of the base. A coil spring is connected between the forward portion of the jaw and a rearward portion of the base. The coil spring defines a tension axis which moves through the pivot axis as the upper jaw is pivoted on the base. The tension axis passes through the pivot axis shortly before the rearmost portion of the upper jaw comes to rest against the rearmost portion of the base.
A trigger is pivotally mounted to the side flanges of the base, forming a second pivot axis below and rearward of the first pivot axis. The trigger has a frontwardly extending tongue and a rearwardmost portion which engages against depending flanges which are integral with the upperjaw. When the trap is opened with a rearwardmost portion of the jaw engaging the rearwardmost portion of the base, the jaw flanges push against the rearwardmost portion of the trigger pivoting the tongue to a raised position. When a rodent pushes the tongue downward, the rearwardmost portion of the trigger rotates about the second axis, pushing against the flanges and causing the upper jaw to rotate about the first pivot axis, bringing the axis of tension below the first pivot axis and causing the teeth of the upper jaw to forcefully close against the teeth of the base.
It is an object of the present invention to provide a rodent trap that is easily set and easily opened to remove dead rodents.
It is another object of the present invention to provide a rodent trap which can be used many times.
It is a further object of the present invention to provide a rodent trap which can be set with one hand.
It is a still further object of the present invention to provide a mouse trap strong enough to kill a mouse yet not harm pets or children.
It is a yet further object of the present invention to provide a rodent trap which is not easily triggered accidentally by vibration.
Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.